Academic literature on the topic 'Bovine Theileria infection'

Theileriosis is a blood piroplasmic disease that adversely affects the livestock industry, especially in tropical and sub-tropical countries. It is caused by haemoprotozoan of the Theileria genus, transmitted by hard ticks and which possesses a complex life cycle. The clinical course of the disease ranges from benign to lethal, but subclinical infections can occur depending on the infecting Theileria species. The main clinical and clinicopathological manifestations of acute disease include fever, lymphadenopathy, anorexia and severe loss of condition, conjunctivitis, and pale mucous membranes that are associated with Theileria-induced immune-mediated haemolytic anaemia and/or non-regenerative anaemia. Additionally, jaundice, increases in hepatic enzymes, and variable leukocyte count changes are seen. Theileria annulata and Theileria parva induce an incomplete transformation of lymphoid and myeloid cell lineages, and these cells possess certain phenotypes of cancer cells. Pathogenic genotypes of Theileria orientalis have been recently associated with severe production losses in Southeast Asia and some parts of Europe. The infection and treatment method (ITM) is currently used in the control and prevention of T. parva infection, and recombinant vaccines are still under evaluation. The use of gene gun immunization against T. parva infection has been recently evaluated. This review, therefore, provides an overview of the clinicopathological and immunopathological profiles of Theileria-infected cattle and focus on DNA vaccines consisting of plasmid DNA with genes of interest, molecular adjuvants, and chitosan as the most promising next-generation vaccine against bovine theileriosis.

Bovine Theileria are tick-borne protozoan parasites that invade bovine erythrocytes and lymphocytes. Three main bovine Theileria species have been identified in China: T. orientalis, T. sinensis, and T. annulata. To examine the prevalence of bovine theileriosis in Yanbian, a total of 584 bovine blood samples were collected from five localities from 2017 to 2019 and analyzed by PCR. Six pairs of oligonucleotide primers directed against the 18S rRNA gene of Theileria spp., Tams-1 gene of T. annulata, MPSP gene of T. orientalis, and T. sinensis, were used to detect these parasites. A sequence analysis of the amplified genes confirmed that the Theileria species were T. orientalis and T. sinensis, without T. annulata. The overall prevalence of Theileria in cattle was 42.81% (250/584). Out of the 584 samples, 159 (27.23%) and 157 (26.88%) were positive for T. sinensis and T. orientalis, respectively, and the mixed infection rate was 11.30% (66/584). The total prevalence of bovine Theileria species in Helong, Hunchun, Longjing, Yanji, and Dunhua was 66.28%, 49.68%, 23.81%, 28.15%, and 0%, respectively. These results provide epidemiological data for the prevention and control of bovine Theileria species in Yanbian, China.

Un stock pathogène de Theileria a été isolé à partir de bovins témoins, lors d'un test d'immunisation sur le terrain contre la theilériose bovine à Kasoba, près de la ville de Karonga au Nord du Malawi. Un stabilat issu de ce stock a causé des fièvres graves et une parasitose prolongée chez du bétail n'ayant jamais été infecté par Theileria parva, provoquant la mort de 5 animaux sur 12 en dépit du traitement. D'un autre côté, ce stock de parasites a seulement causé des réactions légères à modérées chez 17 bovins préalablement immunisés avec un stabilat trivalent de T. parva, excepté chez trois animaux qui ont développé des réactions sévères et l'un d'eux en est mort. Une autre fois, le bétail immunisé avec Theileria parva (Serengeti transformé) provenant de buffle a résisté à une inoculation potentiellement fatale en ne montrant que des réactions légères et modérées. Ce stock de parasites s'est avéré morphologiquement et sérologiquement semblable à Theileria parva (Muguga); il était virulent et pouvait provoquer la mort, en particulier chez du bétail n'ayant jamais été infecté par T. parva. Ce stock de parasites a été ainsi appelé Theileria parva (Kasoba).

Tick-borne pathogens cause economically significant diseases in cattle. Theileria spp. are parasitic protozoa and the causative agent of bovine theileriosis. Here we report the distribution and risk factors of bovine Theileria using blood samples taken between 2018 and 2019. Of 737 tested cattle, nine animals (1.2%) were positive for Theileria orientalis infection by 18S rRNA gene amplification. Further analysis of the infected samples using the T. orientalis major piroplasm surface protein (MPSP) gene revealed five different genotypes circulating in the population: Types 1, 2, 3, 7, and N3. To the best of our knowledge, this is the first research to describe the existence of the T. orientalis MPSP genotype N3 in South Korea. Although the prevalence of bovine T. orientalis was low, our study offers data on the geographical distribution and prevalence of bovine Theileria spp. in South Korea. Further studies are warranted to determine the correlation of clinical symptoms with parasite MPSP genotypes. Our data provide epidemiological information to help control bovine theileriosis in South Korea.

Following incubation with sporozoites of the protozoan parasite Theileria annulata, dendritic cells (DC), extracted from bovine afferent lymph, became infected and transformed into large, rounded, continuously proliferating cell lines. Phenotypic analysis of the transformed cells by immunostaining and flow cytometry revealed that they expressed MHC class I and II antigens, the myeloid marker MyD1 (SIRPα) and the bovine WC6 (workshop cluster 6) molecule. Transformed DC cell lines differed from those produced from infection of macrophages and B cells in that some lines expressed CD21 and a proportion of cells continued to express the antigen stained by the mAb CC81, a marker which defines a subpopulation of DC in afferent lymph. Both of the main populations of DC that have been identified in bovine afferent lymph appeared to be equally permissive for infection and transformation with T. annulata. These findings raise the possibility that the transformed proliferating cells characteristic of in vivo infections could be derived from DC as well as macrophages. This could have consequences for understanding the pathogenesis of the disease and for developing methods to manipulate immune responses to eliminate the parasite.

This study is conducted to investigate Theileria spp. by traditional and molecular methods. A total of 150 blood and 50 lymph samples were collected from local breed symptomatically and asymptomatically cattle of both sexes with age ranging from less than 6 months to more than 1 year during the four seasons of 2018, in different parts at Baghdad city / Iraq. Microscopic examination of Giemsa stained blood smears revealed 39.33 %( 59/150) rate of infection with bovine theileriosis and 34 %( 17/50) positive lymph smears. Statistically no significant difference recorded between female and male: 42.04 % (37/88) and 35.48 % (22/62) respectively. Higher rate of infection 57.97 % (40/69) were recorded in more than 1 year age and 0 % in less than 6 months. 48.93 % (23/47) rate of bovine theileriosis was recorded during summer and 39.53 % (17/43) ; 37.5 % (15/40) rates were recorded during spring and autumn respectively, while the lower rate recorded in winter 20 % (4/20). DNA extraction and polymerase chain reaction (conventional PCR) were done on all cattle blood samples the result recorded that 22 out of 25 samples were positive for Theileria spp and Theileria annulata with percentage of 88 %. Also DNA sequencing analysis and genetic relationship were conducted by phylogenetic analysis.

Le présent article est une revue bibliographique de l’épidémiologie de la theilériose tropicale bovine en Tunisie. C’est une parasitose spécifique due à la présence et à la multiplication dans les phagocytes mononucléés puis dans les érythrocytes d’un protozoaire de la famille des Theileridae, Theileria annulata. Elle est transmise de manière biologique par plusieurs espèces de tiques de la famille des Ixodidae, appartenant au genre Hyalomma. L’implication de trois acteurs très éloignés sur le plan taxonomique est à l’origine d’une maladie dont l’épidémiologie est très complexe. Cette infection évolue selon trois modes enzootiques : (a) l’enzootie stable qui résulte d’un état d’équilibre entre l’hôte et le parasite, (b) l’enzootie instable modérée qui est due à la présence d’une faible population de tiques engendrant des cas cliniques chez des animaux âgés de deux à trois ans, et (c) l’enzootie instable élevée dans laquelle la population de tiques est tellement faible que la probabilité de rencontre entre une tique infectée et un hôte sensible est minime. Le type de situation épidémiologique dans lequel se trouve l’élevage permet de planifier un programme de lutte adapté.

AbstractPiroplasmosis is a tick-borne haemolytic disease caused by different species of the Babesia and Theileria genera. Data on the prevalence of bovine piroplasms and their genetic diversity are scanty in Nigeria. Hence, this study reported the detection of some piroplasms in the blood of cattle in Abeokuta, Nigeria by the polymerase chain reaction (PCR). Blood samples were collected from 252 cattle and subjected to DNA extraction followed by PCR amplification of the partial region of 18S rRNA of the haemoprotozoans. Selected positive amplicons were unidirectionally sequenced and compared to the reference sequences from the Genbank. A total of 220 (87.3 %) cattle were positive for Theileria velifera and/or Babesia bigemina. The T. velifera was detected only in 163 (64.7 %) cattle, while 7 (2.8 %) cattle had a single infection with B. bigemina. Fifty cattle (19.8 %) had mixed infections with both parasites. There were no significant differences in piroplasm infections between the ages of cattle for both parasites. There were no significant differences in infection rates between the sexes for T. velifera, while the males had a significantly higher (P < 0.05) rate of infection for B. bigemina than the female cattle. The molecular detection of Babesia and Theileria species of cattle are reported for the first time in cattle in Abeokuta, Nigeria. This study, which confirmed the endemic nature of the parasites in cattle in the study area, stresses their importance in livestock health and production in Nigeria.

Dissertação de Mestrado Integrado em Medicina Veterinária<br>A Teileriose é uma doença parasitária causada por Theileria spp., transmitida por vectores da família IXODIDAE. Esta hemoparasitose representa uma ameaça à produção de bovinos, em diferentes países, conduzindo a elevadas perdas económicas. São conhecidas várias espécies de Theileria, sendo as mais patogénicas Theileria annulata, agente da Teileriose Tropical ou Mediterrânica, e Theileria parva, agente da Febre da Costa Oriental. Em Portugal, o Ribatejo e o Alentejo são consideradas regiões endémicas de Teileriose Mediterrânica, devido à elevada ocorrência de ixodídeos do género Hyalomma. Os objectivos deste estudo foram: (i) avaliar a presença de Theileria spp. em 112 bovinos de aptidão carne de uma exploração da região do Ribatejo; (ii) estabelecer níveis de infecção para os géneros de hemoparasitas encontrados e (iii) identificar uma amostra de ixodídeos, recolhidos da população em estudo. Através da observação microscópica de esfregaços sanguíneos, detectou-se que a prevalência de Theileria spp. foi de 100%. O género Anaplasma também foi identificado em todos os bovinos estudados. Relativamente aos níveis de infecção de Theileria spp., concluiu-se que o nível I (1-10 merozoítos/10 campos) foi o mais prevalente, tanto nos bovinos reprodutores, com 87,5% (84/96), como nos vitelos, com 37,5% (6/16) dos animais infectados. Estes dados sugerem que a maioria dos animais apresentava infecção subclínica, constituindo um grupo de portadores assintomáticos. Os níveis de infecção II (11-20 merozoítos/10 campos) e III (> 20 merozoítos/10 campos) tiveram uma maior expressão nos vitelos, com 31,3% (5/16) em cada nível, do que nos animais adultos, em que 12,5% (12/96) estavam infectados em nível II e nenhum animal se encontrava infectado em nível III. Os níveis de infecção mais elevados nos vitelos estão de acordo com a maior susceptibilidade destes animais a Theileria spp.. Quanto a Anaplasma spp., o nível de infecção I foi o mais frequente, tanto nos animais reprodutores (60,4%), como vitelos (50%). Dos 92 ixodídeos identificados, 65% (60/92) pertenciam ao género Hyalomma e 35% (32/92) eram Rhipicephalus spp., reconhecidos como vectores de Theileria spp.. Os dados obtidos neste estudo realçam a importância da Teileriose em Portugal. Desta forma, conclui-se ser necessária uma maior investigação acerca da epidemiologia e patogenia da doença.<br>ABSTRACT - THEILERIOSIS IN BEEF CATTLE IN THE RIBATEJO REGION - Theileriosis is a tick-borne disease caused by Theileria spp. protozoa and transmitted by vectors from IXODIDAE family. This parasitic disease constitutes a threat to cattle production in different countries, leading to economic losses. There are various species of Theileria, being T. annulata, the most pathogenic agent in Tropical or Mediterranean Theileriosis, and T. parva, the agent of East Coast Fever. In Portugal, Ribatejo and Alentejo regions are considered endemic for Mediterranean Theileriosis due to the high incidence of ticks of the genus Hyalomma. The aims of this study were: (i) to evaluate the presence of Theileira spp. in 112 beef cattle from a farm located in endemic region of Ribatejo; (ii) to establish blood infection levels and (iii) to identify the genus of the ticks collected in the studied population. Microscopic blood smears observation, showed that Theileria spp. prevalence was 100% either in adults and in calves. The genus Anaplasma was also identified in all the studied animals. Concerning Theileria spp. levels of infection, level I (1-10 merozoits/10 fields) was the most prevalent, both in adult cattle and calves, with 87,5% (84/86) and 37,5% (6/16) respectively. These data suggest that most of the animals had subclinical infection, constituting a group of asymptomatic carriers. Infection levels II (11-20 merozoits/10 fields) and III (> 20 merozoits/10 fields) had a higher expression in calves with 31,3% (5/16) in both, than in adult animals, in which 12,5% (12/96) were infected at level II and no adult animal was infected in level III. The infection levels are highest in calves since these animals are more susceptible to Theileria spp. infection. In relation to Anaplasma spp. infection, level I was the most frequent, in both breeding animals (60,4%) and calves (50%). Of the 92 ticks identified, belonged to the genus Hyalomma, 65% (60/96) and to Rhipicephalus 35% (32/96) recognized as vectors of Theileria spp.. Data obtained in this study emphasizes the importance of theileriosis in Portugal. In this way, further investigation on spreading and pathogenesis of theileriosis is needed.